The anti-tumor agent bleomycin is used clinically, both as a single agent and in combination chemotherapy for the treatment of several types of cancer. For example, bleomycin is efficacious against squamous cell carcinomas and malignant lymphomas. In spite of the obvious utility and importance of the bleomycins as antitumor agents, there are clear opportunities to alter the molecular behavior of bleomycin, and thereby potentially improve its antitumor efficacy. The long-term objectives of this research are the development of bleomycin analogues having improved antitumor efficacy, and an altered spectrum of anti-tumor activity. To achieve these goals, we will prepare libraries of BLM analogues by mix and split synthesis. These libraries will be used to select BLMs having specific desirable properties and the identified analogues will be characterized thoroughly as potential anti-tumor agents.